Stop means for limiting cartridge movement in self-pressurizing ballpoint pens



F. w. BLANCHARD 3,457,019 STOP- MEANS FOR LLML'II'NU CARTRIDGE MOVEMENT 1N SELF-PHE'SSURIZING BALLPOIN'I PENS Filed March 17, 1967 July 22, 1969 flan? M ili/ awep B, W%W

United States Patent 3,457,019 STOP MEANS FOR LIMITING CARTRIDGE MOVE- MENST IN SELF-PRESSURIZIN G BALLPOINT PEN Floyd W. Blanchard, 2334 Loma Vista Place, Los Angeles, Calif. 90039 Continuation-impart of application Ser. No. 441,796, Mar. 22, 1965. This application Mar. 17, 1967, Ser.

Int. Cl. B43k 7/02 US. Cl. 401187 7 Claims ABSTRACT OF THE DISCLOSURE CROSS-REFERENCE TO RELATED APPLICATION This application is a continuation-in-part of copending application Ser. No. 441,796, filed Mar. 22, 1965, now abandoned.

BACKGROUND OF THE INVENTION 7 The background of the invention is set forth in two parts:

Field of the invention The present invention pertains generally to the field of self-pressurizing ballpoint pens and more particularly to stop means for limiting cartridge movement in such pens.

Description of the prior art Reference may be had to the file of said copending application for several prior art patents disclosing self-pressurizing ballpoint pens. Of these, French Patent No. 1,191,405 (April 1959 to Bacon) may be taken as typical.

The cartridge disclosed in this French patent carries a deformable cup in fluid communication with the open end of the cartridge. When a writing force is applied to the Writing tip of the cartridge, the cup is deformed for admitting a compressed volume of air into the cartridge above the ink supply. V

Pens of the type disclosed in this French patent have the disadvantage that actuation of the self-pressurizing means usually results in excessive axial movement of the writing tip. Writers vary in their sensitivity to movement of a writing tip in normal writing. Very few will detect a movement of 0.025 inch or less while some will tolerate a movement of as much as 0.040 inch. It is difiicult to limit self-pressurizing pens of the type disclosed in said French patent to 0.040 inch or less because the design thereof results in cumulative tolerances which must be adhered to from the Writing tip to the other end of the pen.

SUMMARYOF THE INVENTION In view of the foregoing factors and conditions characteristic of prior art self-pressurizing ballpoint pens, it is a primary object of the present invention to provide a selfpressurizing pen not subject to the disadvantages enumerated above and including stop means for limiting cartridge movement.

Another object of the present invention is to provide pressurizing cup means for a self-pressurizing pen which is afiixed to the open end of the pen cartridge and which includes a shoulder engageable with a shoulder provided within the pen casing for limiting axial movement of the cartridge.

Yet another object of the present invention is to provide, in a self-pressurizing ballpoint pen, stop means for limiting cartridge movement to not more than about 0.030 inch.

According to the present invention, a self-pressurizing ballpoint pen is provided with stop means mounted within the pen casing adjacent the orifice end of the cartridge in operative association with the pen cartridge for limiting the axial movement of a Writing element, provided on the cartridge, with respect to a gripping surface provided on the casing adjacent the writing element so that movement of the writing element relativ to the gripping surface by a writing force may be maintained within comfortable writing limits.

In a first embodiment of the present invention, a rigid cup is atfixed to the open end of a ballpoint cartridge in fluid communication therewith. The cup includes an open end engageable with an elastomeric pad provided in the end of the casing for the pen. Deformation of the pad reduces the volume inside the cup forcing compressed air into the cartridge The cup includes an annular shoulder engageable with an annular shoulder provided on the casing for limiting axial movement of the cartridge.

In a second embodiment of the present invention, an

elastomeric cup is used instead of a rigid cup. In this embodiment, an annular shoulder on the cup also engages a shoulder in the casing. The pen is pressurized bydeforming the cup against the end wall of the casing to reduce the volume of the cup :and force a compressed volume of air into the cartridge. The features of the present invention which are believed to be novel are set forth with particularity in the appended claims. The present invention, both as to its organization and manner of operation, together with further objects and advantages thereof, may best be understood by reference to the following description, taken in connection with the accompanying drawings, in which like reference characters refer to like elements in the several views.

BRIEF DESCRIPTION OF THE DRAWING FIGURE 1 is a longitudinal, cross-sectional view of a self-pressurizing pen;

FIGURE 2 is a partial, cross-sectional view similar to FIGURE 1 showing the pen in a pressurized condition;

FIGURES 3 and 4 are partial, cross-sectional views showing a modified form of a pressurizing and shock absorbing means which may be employed in the pen of FIGURE 1 and which includes stop means of the present invention;

FIGURE 5 is a longitudinal, cross-sectional viewof a self-pressurizing pen employing stop means comprising a second embodiment of the present invention; and

FIGURE 6 is a partial cross-sectional view similar to FIGURE 5 showing the pen in a pressurized condition.

Referring again to the drawings and particularly to FIGURES 1 and 2, a self-pressurizing writing implement or pen constituting a first embodiment of the present invention, generally designated 10, includes a container means 12 having a reservoir means 14 containing a noncompressible writing fluid 16 which is influid communication with a writing element 18. The writing element 18 may be of the wick-type, brush type, nib-type or other suitable type of dispensing element and isshown herein for purposes of illustration, but not of limitation, as being of the ballpoint type.

The pen 10 also includes pressurizing means, generally designated 20, in combination with the container means 12 for simultaneously automatically pressurizing the writing fluid 16 and absorbing writing shocks when a writing force is applied to the writing element 18. The means 20 includes a compressible fluid 21, such as air, and a trapping means 22 for trapping a compressed volume of fluid 21 in the reservoir means 14 in fluid communication with the writing fluid 16. The trapping means 22 includes a fluid-compressive or volume reducing means 24 and an orifice means 25 which compress the fluid 21 in reservoir 14 to pressurize the writing fluid 16 when the reservoir means 14 is moved axially so that the orifice means 25, which is provided in the reservoir means 14, engages the volume reducing means 24. The force exerted on the resservoir means 14 when writing pressure is applied to the writing element 18 causes this axial movement.

The reservoir means 14, the writing fluid 16, the compressible fluid 21, the writing element 18 and the orifice means 25 may comprise the elements ordinarily found in a conventional cartridge for a ballpoint pen. Thus, as herein used for purposes of illustration, but not of limitation, the phrase container means includes a conventional cartridge for a ballpoint pen. The container means 12 also includes an elongated casing 26 having an encompassing sidewall 28, an open end 30 and a closed end 32. The closed end 32 is provided with a counterbore 34, an aperture 36 and an air vent 38. The writing element 18 is reciprocally mounted in the aperture 36 so that the reservoir 14 will move slightly axially in the direction of arrow 40 when writing pressure is applied to the writing element 18. The counter bore 34 guides the reservoir 14 during such axial movement and the air vent 38 vents the reservoir means 14 to atmosphere through the orifice means 25 when the container means 12 is in its FIG- URE 1 position.

When the writing element 18 is moved axially in the direction of arrow 40 relatively to a gripping surface 41 provided on the casing 26, the orifice means 25 engages the volume reducing means 24 to simultaneously displace it into the reservoir 14 as shown in FIGURE 2 and to impart flexibility to the writing element 18 by absorbing shocks imparted thereto by a user of the pen 10. The volume reducing means 24 is in the nature of a resilient pad and is mounted in a closure member 42 which closes the open end 30 of the casing 26. The closure member 42 includes a large diameter portion 44 which abuts the open end 30 of casing 26 and a small diameter portion 46 which fits inside the encompassing sidewall 28 with close tolerance. The small diameter portion 46 includes a counter bore 48 forming additional guide means for the reservoir means 14 and a cavity for the volume reducing means or resilient pad 24. The resilient pad 24 may be conveniently made from any suitable material which is soft and resilient such as, for example, rubber or a highlyplasticized, polyvinyl-chloride and the like. The pad 24 may also be somewhat impervious so that it will become readily deformed into the reservoir means 14 as shown in FIGURE 2, seal against orifice means 25 to trap air under pressure in reservoir 14 and readily return to its FIGURE 1 configuration when writing pressure is first applied to the writing element 18 and then released.

It is an important feature of the present invention that the pressurizing means 20 pressurizes the writing fluid 16 only when writing pressure is applied to the writing element 18 by permitting the orifice means 25 to be readily vented to atmosphere through the air vent 38 when writing pressure is released.

The pressurizing means 20 shown in FIGURES 1 and 2 may be advantageously used with pocket-type pens having comparatively short reservoirs. It has been found that the relatively long length and small diameter of the orifice means 25 provided on ballpoint pen cartridges for desktype pens does not permit the resilient pad 24 to displace a suflicient volume of air 21 above the writing fluid 16 to sufficiently pressurize the fluid when the level of the writing fluid drops suificiently in the reservoir means 14 to present a substantial void from the orifice means 25 to the writing fluid 16.

A larger volume of air 21, however, may be displaced in the reservoir 14 by modifying the FIGURE 1 embodiment as shown in FIGURES 3 and 4 wherein a self-pressurizing pen 10a may include a casing 26 and a container means 12 identical to those shown in FIGURE 1. The open end 30 of the casing 26 is closed by a cap 42a which is provided with a counter bore 48a of sufiicient diameter to encompass the casing 26 and accommodate a rigid pressurizing cup 50 which frictionally engages the reservoir means 14 for reciprocation therewith. The cup 50 is provided with an air inlet aperture 52 which communicates with the orifice means 25 for venting the reservoir means 14 to atmosphere and for admitting the compressible fluid 21 thereto. The cup 50 includes a dished portion 54 formed by an annular lip 56 adapted to be brought into sealing engagement with a volume reducing means or resilient pad 24a which is mounted in the cap 420 as shown. When the writing implement 12 is subjected to a writing force, the cup 50 moves in the direction of arrow 40 causing the pad 24a to become displaced into the dished portion 54, as shown in FIGURE 3, reducing the volume of air 21 to pressurize the writing fluid 16. The lip 56 forms an efiFective seal with the pad 24a trapping a com pressed volume of air 21 in reservoir means 14 so that the writing fluid 16 remains pressurized as long as the reservoir means 14 is in its FIGURE 3 position. In this position, the pad 24a also serves as a suitable shock absorber imparting flexibility to the writing element 18. When writing pressure is removed from the writing element 18, the resiliency of the pad 24a causes the reservoir means 14 to move to its FIGURE 4 position venting reservoir means 14 to atmosphere through orifice means 25 and the air vent 38 shown in FIGURE 1. Proper venting may be assured by providing one face 58 of the pad 24a with an irregular surface as indicated at 60.

It is apparent that the annular shoulder formed by surface of rigid cup 50 which is adjacent open end 30 of casing 26 may be used as a first stop means for engaging open end 30 of casing 26 to limit axial movement of reservoir 14.

Referring now to FIGURES 5 and 6, a self-pressurizing pen constituting a second embodiment of the present invention, generally designated 10b, includes a container means 12b in the form of a ballpoint pen cartridge having a reservoir means 14b containing a non-compressible writing fluid 16b which is in fluid communication with a writing element 18b.

The pen 10b also includes pressurizing means, generally designated 20b, in combination with the container means 12b for simultaneously automatically pressurizing the writing fluid 16b and absorbing writing shocks when a writing force is applied to the writing element 18b. The means 20b includes a compressible fluid 21b, such as air, and a trapping means 22b for trapping a compressed volume of fluid 21b in the reservoir means 14b in fluid communication with the writing fluid 16b. The trapping means 22b includes a fluid-compressive or volume reducing means 24 and an orifice means 25 which compress the fluid 21b in reservoir means 14b to pressurize the writing fluid 16b when the reservoir means 14b is moved axially so that the orifice means 25b, which is provided in the reservoir means 14b, engages the volume-reducing means 24b. The force exerted on the reservoir means 14b when writing pressure is applied to the writing element 18b causes this axial movement.

The container means 12b is reciprocably mounted in an elongated casing 26b having an encompassing sidewall 28b, an open end 30b and a closed end 32b. The

18b is reciprocally mounted in the aperture 36b so that the reservoir means 14b will move slightly axially in the direction of arrow 40b when writing pressure is applied to the writing element 18b. The counter bore 34b guides the reservoir means 14b during such axial movement and the air vent 38b vents the reservoir means 14b to atmosphere through the volume-reducing means 24b and orifice means 25b when the container means 12b is in its FIG- URE 5 position.

The open end 30b of the casing 26b is closed by a cap 42b which is provided with a counter bore 48b of sufiicient diameter to encompass the casing 26b and accommodate the volume-reducing means 24 which is like the rigid pressurizing cup 50 shown in FIGURES 3 and 4 except that the volume-reducing means 24b is made from an elastomeric material having a hollow cylindrical neck 62 frictionally engaging the reservoir means 14b for reciprocation therewith. The volume-reducing means 24b is provided with an air-inlet aperture 52b which communicates with the orifice means 25b for venting the resservoir means 14b to atmosphere and for admitting the compressible fluid 21b thereto. The means 24b includes a dished portion 54b formed by an annular lip 56b adapted to be brought into sealing engagement; with a sealing surface 64b comprising the inner surface of the end wall portion 66b of cap 42b. When the writing implement 12b is subjected to a Writing force, the cup 50b moves in the direction of arrow 40b causing the lip 56b to become deformed, as shown in FIGURE 6, reducing the volume of compressible fluid or air 21b to pressurize the writing fluid 16b. The lip 56b forms an effective seal with the seating surface 64b trapping a compressed volume of air 21b in reservoir means 14b so that the writing fluid 16b remains pressurized as long as the reservoir means 14b is in its FIGURE 6 position. In this position, the lip 56b also serves as a suitable shock-absorber imparting flexibility to the writing element 18b. It should be noted that the dished portion 54b may bottom-out on sealing surface 64b under heavy writing pressures. When Writing pressure is removed from the writing element 18b, the resiliency of the lip 56b causes the reservoir means 14b to move to its FIGURE 5 position venting reservoir means 14b to atmosphere through orifice means 25b, aperture 52b, lip 56b and air vent 38b.

The cup 24b includes an annular shoulder 68b constituting a first stop means engageable with the annular shoulder 70b forming open end 30b of easing 26b and constituting a second stop means. The stop means 68b and 70b limit axial movement of the cartridge 12b in the direction of arrow 72b and a stop means formed by the seating surface 64b and the lip 56b limits movement of the cartridge 12b in the direction of arrow 40b.

The second stop means 70b constitutes a forward limit stop at the same end of the cartridge 12b as the pressurizing means b. Locating the forward limit stop at this end of the cartridge minimizes the number of close manufacturing tolerances which have to be maintained as is the case when the closed end wall 32b is relied upon for the forward limit stop. For example, the normal manufacturing tolerance for the casing 26b between a forward limit stop defined by a plane AA passing through end wall 32b and a plane BB passing through forward limit stop means 70b lies within the range of :0.005 to $0.010 inch. In addition, the normal manufacturing tolerance between a plane C-C passing through the portion of cartridge 12b which engages end wall 3217 at plane AA and a plane D-D passing through orifice means b is 0.005 inch. The normal manufacturing tolerance between a plane BB passing through the annular shoulder or stop means 68b and a plane F-F passing through the annular lip 56b is 1:0.002 inch and the tolerance between plane BB and a plane G--G passing through seating surface 64b is 10.002 inch. In addition, the deformation of the lip 56b required for proper pressurization is approximately 0.012 inch. Without the stop means 68b and 70b, these tolerances may add up to as much as 0.040 inch, well into the range where all writers will detect point movement or a spongy feel not acceptable by a great many writers. However, with the stop means 70b, and 68b, the normal manufacturing tolerance results in a maximum movement of 0.008 inch which, when combined withthe 0.012 inch required to pressurize the pen results in a total movement of 0.020 inch, well. within the range where few writers detect a movement.

As used herein, the phrases closure member 42 and cap 42b shall be construed to include the phrase seat means.

While the particular self-pressurizing pens and limit stop means herein shown and described in detail are fully capable of attaining the objects and providing the advantages hereinbefore stated, it is to be understood that they are merely illustrative of the presently preferred embodiments of the invention and that no limitations are intended to the details of construction or design herein shown other than as defined in the appended claims.

What is claimed is:

1. In a ballpoint pen including casing means having a gripping surface, which may be gripped by a user of said pen during writing operations, an air vent open to atmosphere, a first end provided with an aperture and a second end, seat means provided at said second end, said pen also including a ballpoint-pen cartridge reciprocally mounted in said casing means, said seat means being mounted in the line of reciprocation of said cartridge, said cartridge including a ballpoint-type writing element at one end, orifice means at another end and an inkcarrying reservoir between said ends and pressurizing means mounted in said casing means intermediate said reservoir and said seat means for sealing said orifice means from said vent and for trapping a compressed volume of atmospheric air in operative association with said reservoir when said writing element is moved relatively to said gripping surface by the thrust of a writing force applied to said writing element, said seat means receiving said writing thrust and transferring it to said casing, the improvement comprising:

stop means mounted in said casing means adjacent said seat means, said stop means including a reciprocating means carried by said cartridge for reciprocation therewith and a stationary means carried by said casing means, said reciprocating means engaging said stationary means for limiting the axial movement of said writing element away from said seat means when said writing thrust is removed, whereby movement of said writing element relative to said gripping surface by said writing force may be maintained within comfortable writing limits.

2. The improvement as stated in claim 1 wherein said axrlal movement is limited to not more than about 0.030 mc 3. improvement as stated in claim 1 wherein said pressurlzing means includes cup means surrounding said orifice means, said reciprocating means comprising first shoulder means on said cup means and said stationary means comprising second shoulder means in said pen.

4. An improvement as stated in claim 3 wherein said cup means is rigid.

5. An improvement as stated in claim 3 wherein said cup means is made from an elastomeric material.

6. An improvement as stated in claim 4 wherein said cup means includes an open end and wherein said pressurizing means includes an elastomeric pad mounted in said casing means for engagement by said open end of said cup means.

7. An improvement as stated in claim 5 wherein said casing means includes an open end defining said second shoulder means, said open end being covered by said seat means, said seat means including a sealing surface engageable by said cup means for deforming said cup means to trap said compressed volume of atmospheric air.

(References on following page) References Cite $1,191,405 4/1959 France. UNITED STATES PATENTS 926,054 4/1955 Gy m y ,s7o,742 1 1959 H km 401 135, 1 2 ac yer A LAWRENCE CHARLES, Prlmary Examlner FOREIGN PATENTS 5 r r 995,271 8/ 1951 France. 

